Penetration and Expansion Testing

[remtom1200]

I predict the mr hollowpoints will create enough pressure at higher fps to swell the soap block to the point it will break open.

[rsterne]

One last set of test for those interested in hunting with Non-PAL airguns.... I tested a variety of pellets in both .177 and .22, using a 2289 based rifle, pumped to give just over 400 fps with a 7.9 gr. pellet in .177 and the same velocity with 14.3 gr. in .22 cal.... Since we are mostly interested in how hollowpoint pellets might expand, I chose those velocities as representative of what they might arrive at 20-25 yards at when shot from a Non-PAL gun.... Here are the results, first in .177:



From left to right:
RWS Hobby 7.1 gr.
RWS Super HollowPoint 7.1 gr.
H&N Terminator 7.1 gr.
Crosman Destroyer 8.0 gr.
Crosman Premier Hollowpoint 8.0 gr.
JSB Exact Express 7.8 gr.
JSB Predator Polymag 8.2 gr.
Beeman Round 8.4 gr.
H&N Crow Magnum 8.8 gr.
H&N Baracuda 10.2 gr.
JSB Monster 13.5 gr.
H&N Rabbit Magnum 16.4 gr.

Not one single pellet expanded, they all looked like they just came out of the tin (except for rifling marks).... Now the .22 cal (photo to same scale):



From the left; H&N Crow Magnum 18.0 gr.
Bottom row, left to right:
RWS Hobby 11.9 gr.
RWS Super HollowPoint 14.3 gr.
Crosman Wadcutter 14.3 gr.
Crosman Premier HP 14.3 gr.
JSB Exact Express 14.3 gr.
Gamo Round 15.4 gr.
JSB Predator Polymag 16.2 gr.
JSB Exact Heavy 18.1 gr.
H&N Baracuda 30.9 gr.
JSB Exact Monster 25.3 gr.
H&N Rabbit Magnum 24.8 gr.

Again, not one single pellet showed any expansion.... I can say with confidence that in a Non-PAL airgun you should simpy use the pellet that is the most accurate for your gun, period.... The wadcutters left a slightly larger entrance hole and penetrated less.... The roundballs penetrated the greatest amount, closely followed by the round-nosed, and although I didn't test any pointed pellets, previous tests have showed little difference from a round nose of similar weight.... Heavier pellets tended to penetrate further that light ones, even though they were going slower....

One other thing should be obvious.... The .22 pellets generally penetrated further, and made a bigger wound channel.... Penetration in .177 varied from 13-22 mm (averaging under 3/4"), while in .22 cal it was from 19-29 mm (averaging over 1").... There is little magic in that, as at the same velocity, and being heavier, they have a lot more FPE, and hence a lot more punch.... That's not a lot of penetration to dispatch anything much bigger than a starling or a rat.... so if you're hunting with a Non-PAL airgun, take your best shot, within 25 yards, and be realistic....

Bob

[remtom1200]

Possibly at lower velocity the skirt is not expanding enough to make a proper seal? It doenst look like very deep grooves, but I'm left wondering if the heavier band at the skirt area may be the culprit. Or I suppose the opposite could be true as well...too tight for the barrel and air is escaping at the weakest point which may be the bolt probe seal?

[AirGunEric]

Where did you find the best melt-pour clear soap for the tests?

[Fastair]

Thanks for posting all the information Bob. This is a super post.

[Doc Sharptail]

This is great info! I don't know how I missed it.

The information on the powder .22's practically mirrors my field experience. There is an exception though- apart from the hollow points, I found the CCI short CB cap to be a clean taker of grouse. Identical to the 710 fps you mentioned. The bullets on these were soft- they easily marred with a finger nail, like the old 60-40 lead solder. I found them to be very accurate in guns that were marked s,l, lr.

The crow magnums in .22 would be worth investigating, for me...

Regards,

Doc Sharptail